Use of a thermotropic liquid crystal polymer is expanding for various uses because the liquid crystal polymer is excellent in the mechanical properties such as the heat resistance and the rigidity, the chemical resistance, the dimension precision, and the like. Hereinafter, a thermotropic liquid crystal polymer will be referred to as a liquid crystal polymer or LCP.
Especially, as to devices in the fields of information and communication such as a personal computer and a mobile phone, an increase of the integration density, downsizing, a reduction of the thickness and a reduction of the height of their parts are rapidly advanced, and a very thin portion may often be formed in the parts. The use amount of a liquid crystal polymer has therefore significantly increased utilizing the features of a liquid crystal polymer which are not found in other resins such as the excellent moldability, that is, the satisfying fluidity and the avoidance of any burr.
However, the reduction of the thickness, and complication in the shapes of the electronic parts used in the information and the communication fields are advanced day by day. Accordingly, further improvement of the fluidity during molding is demanded to a liquid crystal polymer.
Many methods of improving the fluidity of a liquid crystal polymer during molding are known. For example, Patent Document 1 discloses a method of additionally blending a liquid crystal polymer having a specific molecular weight. Patent Document 2 discloses a method of including in a liquid crystal polymer an oligomer of 4-hydroxybenzoic acid exhibiting a specific flow temperature. Patent Document 3 discloses a method of producing a liquid crystal polymer by the deacetation melt polymerization in which a polymerization reaction liquid is supplied to a vertical stirring thin-film evaporator and is passed therethrough to reduce the amount of an acetic acid generated in the resulting liquid crystal polymer; and a liquid crystal polymer excellent in the fluidity is thereby acquired. Patent Document 4 discloses a method of adding a phosphoric acid-based compound during the production of a liquid crystal polymer.
However, the methods disclosed in Patent Document 1 and Patent Document 2 have a problem that a liquid crystal polymer having a specific molecular weight and an oligomer of 4-hydroxybenzoic acid exhibiting a specific flow temperature are not easily produced. The method disclosed in Patent Document 3 has a problem that a special apparatus such as a vertical stirring thin-film evaporator has to be used. The method disclosed in Patent Document 4 has a problem that the mechanical properties of a liquid crystal polymer may significantly be degraded depending on the type and the use amount of a phosphoric acid-based compound.
Because of the above, there is a need for a liquid crystal polymer in which the fluidity during molding is improved without the deterioration of mechanical properties of the liquid crystal polymer using inexpensive and easily available materials and employing no special apparatus.    Patent Document 1: Japanese Patent Publication No. 2-173156    Patent Document 2: Japanese Patent Publication No. 3-095260    Patent Document 3: Japanese Patent Publication No. 2000-309636    Patent Document 4: Japanese Patent Publication No. 06-032880